I been taking topamax for 2 days 50 mg 2 times a day and this my third day. can i stop cold turkey very bad side effects?

Many uses: Topamax has many uses. It is a medicine that is used for Epilepsy, beside using it for other conditions like migraine, alcoholism, obesity and in some psychiatric conditions. What are you taking it for?! I would advise you to consult the prescribing doctor before changing the dose of the medication or stopping it as potentially such an action might cause more harm to you.

Yes: it's unlikely your body has gotten used to topamax after only 2-3 days so you should be fine stopping it, but before you do speak with the prescribing physician to ensure it is safe to do so, for instance: if it was started as an adjunct to seizures, due to poor control, stopping cold turkey may be more consequential than if it was started for migraines or wt loss.